[PATCH 30/39] scsi: centralize command re-queueing in scsi_dispatch_fn

Christoph Hellwig
2014-03-17T13:31:36Z

[-- Attachment #1: 0030-scsi-centralize-command-re-queueing-in-scsi_dispatch.patch --]
[-- Type: text/plain, Size: 3248 bytes --]

Make sure we only have the logic for requeing commands in one place.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
drivers/scsi/scsi.c | 36 +++++++++++++-----------------------
drivers/scsi/scsi_lib.c | 9 ++++++---
2 files changed, 19 insertions(+), 26 deletions(-)

diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index 0e8a077..0df3913 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -639,9 +639,7 @@ int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
* returns an immediate error upwards, and signals
* that the device is no longer present */
cmd->result = DID_NO_CONNECT << 16;
- scsi_done(cmd);
- /* return 0 (because the command has been processed) */
- goto out;
+ goto done;
}

/* Check to see if the scsi lld made this device blocked. */
@@ -653,16 +651,8 @@ int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
* occur until the device transitions out of the
* suspend state.
*/
-
- scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
-
SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
-
- /*
- * NOTE: rtn is still zero here because we don't need the
- * queue to be plugged on return (it's already stopped)
- */
- goto out;
+ return SCSI_MLQUEUE_DEVICE_BUSY;
}

/*
@@ -686,35 +676,35 @@ int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
"cdb_size=%d host->max_cmd_len=%d\n",
cmd->cmd_len, cmd->device->host->max_cmd_len));
cmd->result = (DID_ABORT << 16);
-
- scsi_done(cmd);
- goto out;
+ goto done;
}

if (unlikely(host->shost_state == SHOST_DEL)) {
cmd->result = (DID_NO_CONNECT << 16);
- scsi_done(cmd);
- } else {
- trace_scsi_dispatch_cmd_start(cmd);
- cmd->scsi_done = scsi_done;
- rtn = host->hostt->queuecommand(host, cmd);
+ goto done;
+
}

+ trace_scsi_dispatch_cmd_start(cmd);
+
+ cmd->scsi_done = scsi_done;
+ rtn = host->hostt->queuecommand(host, cmd);
if (rtn) {
trace_scsi_dispatch_cmd_error(cmd, rtn);
if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
rtn != SCSI_MLQUEUE_TARGET_BUSY)
rtn = SCSI_MLQUEUE_HOST_BUSY;

- scsi_queue_insert(cmd, rtn);
-
SCSI_LOG_MLQUEUE(3,
printk("queuecommand : request rejected\n"));
}

- out:
SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
return rtn;
+ done:
+ SCSI_LOG_MLQUEUE(3, printk("scsi_dispatch_cmnd() failed\n"));
+ scsi_done(cmd);
+ return 0;
}

/**
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 9889c75..53d06e8 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1598,9 +1598,12 @@ static void scsi_request_fn(struct request_queue *q)
* Dispatch the command to the low-level driver.
*/
rtn = scsi_dispatch_cmd(cmd);
- spin_lock_irq(q->queue_lock);
- if (rtn)
+ if (rtn) {
+ scsi_queue_insert(cmd, rtn);
+ spin_lock_irq(q->queue_lock);
goto out_delay;
+ }
+ spin_lock_irq(q->queue_lock);
}

return;
@@ -1620,7 +1623,7 @@ static void scsi_request_fn(struct request_queue *q)
blk_requeue_request(q, req);
atomic_dec(&sdev->device_busy);
out_delay:
- if (atomic_read(&sdev->device_busy) == 0)
+ if (atomic_read(&sdev->device_busy) == 0 && !scsi_device_blocked(sdev))
blk_delay_queue(q, SCSI_QUEUE_DELAY);
}

--
1.7.10.4